Moldable articles, method of making same and method of molding

ABSTRACT

A moldable article, including at least a container made of a barrier material, the container providing an interior space within which a plurality of glass particles are contained. The glass has a glass transition temperature and a crystallization onset temperature, the difference between the glass transition temperature and the crystallization onset temperature is at least about 5° K., and the glass is composed of at least two metal oxides, from 0 to less than 20% by weight SiO 2 , from 0 to less than 20% by weight B 2 O 3 , and from 0 to less than 40% by weight P 2 O 5 . The moldable article protects the glass particles by keeping them clean and moisture free prior to a molding operation. A method of making a moldable article includes: removing entrapped moisture from a plurality of glass particles, placing glass particles in a receptacle, and sealing the receptacle to form the article. The moldable article may be placed in a mold and, during the molding process, the barrier material essentially burns off while the glass particles coalesce into a molded article.

The present invention relates to moldable articles for the molding ofglass particles, to methods of preparing the moldable articles and tomethods of molding the moldable articles.

BACKGROUND

Glass compositions have been used to provide large articles and/orcomplex shapes. Such articles are often made by coalescing particles ofglass. Recently, such articles and complex shapes have been made usingmicroparticles of non-traditional glass materials.

The manufacture of molded glass articles is accomplished in a moldingprocess in which glass particles are heated above the glass transitiontemperature of the material. The melting particles coalesce and, uponcooling, assume a solidified shape to form the article. The moldingprocess typically involves the application of pressure on the meltingparticles to aid in shaping the molten glass into the form dictated bythe particular mold design.

In the utilization of molding techniques to make glass articles, smallglass particles (e.g., microparticles) are known to collect moistureand/or static charge. This is especially true in the manufacture ofarticles from microparticles of non-traditional glass materials. As aresult, glass particles are difficult to handle during the moldingprocess.

SUMMARY

The present invention addresses problems encountered in the molding ofglass materials. In one aspect, the invention provides a moldablearticle, comprising:

-   -   A first container comprising a first barrier, the first barrier        comprised of a first material, and an interior space within the        first barrier;    -   A plurality of first glass particles contained within the        interior space and comprising a first glass, the plurality of        first glass particles being moldable at a first molding        temperature, the first glass having a first glass transition        temperature and a first crystallization onset temperature, the        difference between the first glass transition temperature and        the first crystallization onset temperature being at least about        5° K., the first glass having a composition comprising at least        two metal oxides, from 0 to less than 20% by weight SiO₂, from 0        to less than 20% by weight B₂O₃, and from 0 to less than 40% by        weight P₂O₅; and    -   Wherein, the first material has a first decomposition        temperature less than the first molding temperature.

In some embodiments, the interior space of the foregoing article isdivided into multiple spaces, including a first interior space and asecond interior space with the plurality of first glass particlescontained within the first interior space and a plurality of secondglass particles contained within the second interior space, the secondglass particles comprising a second glass having a composition differentthan the composition of the first glass.

In other embodiments, the moldable article further comprises:

-   -   A second container comprising a second barrier, the second        barrier comprised of a second material, and a second interior        space within the second barrier, the second container being        wholly within the interior space of the first container; and    -   A plurality of second glass particles contained within the        second interior space so that the plurality of second glass        particles and the plurality of first glass particles are        separated from one another, the plurality of second glass        particles comprising a second glass, the plurality of second        glass particles being moldable at a second molding temperature.

In another aspect, the invention provides a method of making a moldablearticle, the method comprising:

-   -   Placing a plurality of first glass particles in a first        receptacle, the plurality of first glass particles being        moldable at a first molding temperature, the first glass having        a first glass transition temperature and a first crystallization        onset temperature, the difference between the first glass        transition temperature and the first crystallization onset        temperature being at least about 5° K., the first glass having a        composition comprising at least two metal oxides;    -   Removing entrapped moisture from the first glass particles; and    -   Sealing the first receptacle to form a first container        comprising a first barrier, the first barrier defining an        interior space, the plurality of first microparticles occupying        at least a portion of the interior space, wherein the interior        space is substantially free of water, and wherein the first        barrier comprises a first material having a first decomposition        temperature lower than the first molding temperature.

In some embodiments of the foregoing method, the method furthercomprises:

-   -   Placing a plurality of second glass particles in a second        receptacle, the plurality of second glass particles comprising a        second glass that is moldable at a second molding temperature;    -   Removing entrapped moisture from the second glass particles; and    -   Sealing the second receptacle to form a second container        comprising a second barrier, the second barrier defining a        second interior space, the plurality of second glass particles        occupying at least a portion of the second interior space,        wherein the second barrier comprises a second material having a        second decomposition temperature lower than the second molding        temperature; and    -   Placing the second container within the first receptacle prior        to the step of sealing the first receptacle.

In still other embodiments of the foregoing method, the first receptaclecomprises a plurality of chambers, and the step of placing the pluralityof first glass particles in the first receptacle comprises placing theparticles in a first chamber; the method further comprising placing asecond plurality of glass particles in a second chamber, wherein thestep of sealing the first receptacle forms the first container so thatthe interior space forms a plurality of sealed chambers with the firstplurality of glass particles sealed within a first interior space andthe second plurality of glass particles sealed within a second interiorspace.

In still another aspect, the invention provides a method for molding anarticle, comprising:

-   -   Placing one or more of the foregoing moldable articles in a mold        cavity; and    -   Heating the mold cavity to decompose the first material and        coalesce the glass particles to provide a molded article.

In general, terms used in the description of the embodiments of thepresent invention shall be understood as having the common meaning givento them, as understood by the person of ordinary skill in the art.However, certain terms shall have the meaning set forth herein.

“Amorphous material” refers to material derived from a melt and/or avapor phase that lacks any long range crystal structure as determined byX-ray diffraction and/or has an exothermic peak corresponding to thecrystallization of the amorphous material as determined by aDifferential Thermal Analysis.

“Ceramic” includes amorphous material, glass, crystalline ceramic,glass-ceramic, and combinations thereof.

“Glass” refers to amorphous material exhibiting a glass transitiontemperature.

“Glass-ceramic” refers to ceramic comprising crystals formed byheat-treating amorphous material.

“Inert gas” refers to helium, neon, krypton, argon, xenon, nitrogen andcombinations of two or more of the foregoing.

The various features of the disclosed embodiments will be furtherunderstood by those skilled in the art upon consideration of theremainder of the disclosure, including the Detailed Description, thenon-limiting Examples and the appended Claims.

BRIEF DESCRIPTION OF THE FIGURES

In describing the embodiments of the invention, reference is made to thevarious Figures. It will be appreciated that the Figures are not toscale but are provided as an aid in describing the embodiments. Thevarious features of the embodiments are identified with referencenumerals wherein like numerals generally indicate like features, andwherein:

FIG. 1 is a plan view of a moldable article according to an embodimentof the invention;

FIG. 2 is a side view of the moldable article of FIG. 1;

FIG. 3 is a schematic representation of a process for the manufacture ofthe moldable article of FIG. 1 and also illustrating the subsequentmolding thereof;

FIG. 4 is a plan view of a moldable article according to anotherembodiment of the invention;

FIG. 5 is a schematic representation of a process for the manufacture ofthe moldable article of FIG. 4 and also illustrating the subsequentmolding thereof;

FIG. 6 is a plan view of a moldable article according to anotherembodiment of the invention;

FIG. 7 is a perspective view of a moldable article according to stillanother embodiment of the invention;

FIG. 8 is a perspective view of a molded article according to stillanother embodiment of the invention;

FIG. 9 is a perspective of a molded article according to still anotherembodiment of the invention;

FIG. 10 is a perspective of a molded article according to still anotherembodiment of the invention; and

FIG. 11 is a perspective of a molded article according to still anotherembodiment of the invention.

DETAILED DESCRIPTION

The invention provides for the handling of glass, includingnon-traditional glass, wherein the glass is initially in the form ofparticles (spherical particles, fibers, microspheres, etc..). Theembodiments of the invention provide moldable articles comprising glassparticles, processes for the preparation of moldable articles andprocesses for molding. In the various embodiments, moldable articles areprovided in the form of a sealed container or package containing glassparticles in a moisture-free, controlled and/or treated atmosphere. Themoldable articles described herein may be inserted directly into a moldcavity. A molding operation is performed by the application ofheat/pressure to the moldable article without removing the glassparticles from the package. The molding process is carried out attemperatures above the decomposition temperature of the packagingmaterial so that the packaging essentially burns off during the moldingoperation. The glass typically has a molding temperature (e.g., atemperature at which the glass particles begin to coalesce)significantly higher than the decomposition temperature of the packagingmaterial. At or above the molding temperature for the glass, the glassparticles coalesce and, upon cooling, provide a molded article.

Referring now to the Figures, FIGS. 1 and 2 provide different views of amoldable article 10 according to an embodiment of the invention. Themoldable article 10 is provided in the form of a first package having afirst barrier 12 defining a first interior space 14 containing apredetermined amount (e.g., a plurality) of glass particles 16. Thefirst barrier 12 is sealed, and the first interior space typically hasan atmosphere different than the atmosphere surrounding the article 10.In some embodiments, the first interior space 14 has an atmospheresubstantially free of water vapor. In some embodiments, the firstinterior space 14 has an atmosphere of inert gas. In other embodiments,the atmosphere in first interior space 14 is at least partiallyevacuated to a reduced pressure (e.g., vacuum or near vacuum).

First barrier 12 is made of a flexible first material that issubstantially gas impermeable in order to maintain a substantiallyconstant atmosphere within the first interior space 14. While thearticle 10 remains sealed, glass particles 16 and first interior space14 remain substantially dry or water-free.

Suitable flexible first materials include paper as well as variousflexible polymer materials. As used herein, the term “flexible” refersto a property, and materials having such a property typically lackrigidity or stiffness under ambient conditions. In other embodiments,first barrier may be made of a more rigid first material. As usedherein, the term “rigid” refers to a property, and a material havingsuch a property tends to maintain a given shape at ambient temperaturesin the absence of excess heat or external forces exerted on thematerial. However, a rigid material need not be entirely inflexible and,in fact, some rigid materials may be bent or otherwise deformed whenheated, handled or the like. It will be appreciated that the differencesbetween a rigid material and a flexible material may be accounted for,in some instances, by the use of different materials or by variations inthe thickness of the same or similar material (e.g., increasing thethickness of a material can provide rigidity).

Polymers suitable for use as the first material include those selectedfrom the group consisting of polyamide, poly methyl methacrylate,polyisobutylene, polycarbonate, polyethylene carbonate, polypropylenecarbonate, polybutylene terephthalate, polyetheretherketone,polyethylene, polypropylene, polyphenylene oxide, polystyrene aromaticpolyesters, and combinations of two or more of the foregoing. Suitablepolyamides include nylon 6 and nylon 66 and combinations thereof.Suitable polyethylenes can be selected from low density polyethylene,high density polyethylene, medium density polyethylene and combinationsof two or more of the foregoing. In specific embodiments, the firstbarrier is made with low density polyethylene. The first material has afirst decomposition temperature at which the material decomposes.

Glass particles 16 occupy the first interior space 14. In embodiments ofthe invention, the particles 16 are microparticles comprising a firstglass material that is a non-traditional glass material such as thosedescribed in patents and patent applications that include U.S. Ser. Nos.09/922,527, 09/922,528, and 09/922,530, filed Aug. 2, 2001; U.S.2003/0115805 A1 (Rosenflanz et al.); U.S. 2003/0110707 A1 (Rosenflanz etal.); U.S. Pat. No. 7,168,267 (Rosenflanz et al.); U.S. 2003/0126802 A1(Rosenflanz); U.S. Pat. No. 7,147,544 (Rosenflanz et al.); and U.S. Pat.No. 7,101,819 (Rosenflanz et al.), the disclosures of which areincorporated herein by reference.

The aforementioned non-traditional glass materials have a first glasstransition temperature and a first crystallization onset temperature.The difference between the first glass transition temperature and thefirst crystallization onset temperature is at least about 5° K. (oreven, at least 10° K., at least 15° K., at least 20° K., at least 25°K., at least 30° K., or at least 35° K.). The first glass materialcomprises at least two metal oxides (i.e., the metal oxides do not havethe same cation(s)), from 0 to less than 20% by weight SiO₂ (e.g., lessthan 15%, less than 10%, less than 5% by weight, or even zero percent,by weight, SiO₂), from 0 to less than 20% by weight B₂O₃ (e.g., lessthan 15%, less than 10%, less than 5% by weight, or even zero percent,by weight, B₂O₃), and from 0 to less than 40% by weight P₂O₅ (e.g., lessthan 35%, less than 30%, less than 25%, less than 20%, less than 15%,less than 1%, less than 5% by weight, or even zero percent, by weight,P₂O₅). The foregoing glass materials are moldable at or above a firstmolding temperature at which the microparticles begin to coalesce. Inthe embodiments of the invention described herein, the firstdecomposition temperature of the first material is lower than the firstmolding temperature of the first glass.

Referring to FIG. 3, a process for the preparation of moldable article10 is schematically shown along with a molding process involving thearticle. A measured quantity of glass particles 16 are heated within acontainer 20 at a heating station (not shown) such as an oven, a heatingmantle or the like. The particles 16 are heated to an elevatedtemperature below the T_(g) of the glass for a sufficient time to removewater. In some embodiments, the particles are held at a temperature nearthe boiling point of water (e.g., 100° C.). In some embodiments, asuitable temperature is in the range from about 101° C. to about 150°C., from about 110° C. to about 140° C., and from about 120° C. to about135° C. In some embodiments, a suitable temperature is about 130° C. Theamount of time the particles are heated can depend on the volume ofparticles being used as well as the amount of moisture present. Invarious embodiments, heating for several hours is desired to ensure theparticles are adequately dry, and the particles can be heated for up toabout 24 hours at a temperature in one of the foregoing ranges.

Once dried, container 20 may be sealed (not shown) and the glassparticles 16 are allowed to cool before being transferred from container20 into sealable flexible container 26. Funnel 28 is shown as anoptional means to facilitate the transfer of the particles 16. Followingtransfer of the glass particles, sealable container 26 is filled with aquantity of dried particles, and the container 26 can be sealed alongits opened end 30 to provide moldable article 10 with an interior space14 that is substantially moisture-free. In some embodiments, sealablecontainer 26 is purged with inert gas prior to sealing. In someembodiments, the container 26 is sealed to have a reduced pressurewithin first interior space 14. In some embodiments, container 26 issealed to provide a vacuum or near vacuum conditions within interiorspace 14.

The moldable article 10 is suitable for use in a molding process to moldthe glass particles 16 into a molded article. In embodiments in whichthe glass particles 16 are in the form of microparticles, they may be ofan average diameter measured in micrometers, and in some embodiments inthe range from about 10 μm to about 250 μm. In any event, the glassparticles 16 are moldable at a first molding temperature at or aboveabout 300° C., at or above about 400° C., at or above about 500° C., ator above about 700° C. or at or above about 900° C. In the moldingprocess, moldable article 10 is placed in mold cavity 34 of mold 32. Inthe embodiment of FIG. 3, the depicted molding process is compressionmolding, and cavity 34 is equipped to be heated to an elevatedtemperature. With moldable article 10 in the cavity 34, mold 32 isclosed with a top or plug member 36 dimensioned to fit within the cavity34 to apply pressure to the material within the mold.

The mold 32 is heated to a first molding temperature and the mold ispressurized by the compression exerted by plug member 36. In the variousembodiments of the invention, the first barrier of the moldable article10 comprises a first material (e.g., polyethylene) having adecomposition temperature lower than the first molding temperature ofthe glass particles so that the first material of barrier 12 decomposesduring the molding process and typically before the particles 16 beginto soften and coalesce. In some embodiments, decomposition of the firstbarrier 12 removes substantially all of the first material of thebarrier. As the temperature within mold 32 continues to rise to thefirst molding temperature, the glass particles begin to soften, coalesceand assume a shape that is consistent with the interior configuration ofcavity 34. The mold 32 is then cooled to form the molded article 38which may then be removed from the cavity 34.

In embodiments, the non-traditional glass particles are coalesced andare at least partially crystallized to provide a glass-ceramic articleor a ceramic article. In some embodiments, the glass is heat treated toincrease the crystallinity of the glass and provide glass-ceramic orceramic material. Those skilled in the art will appreciate that themolded article 38 may comprise glass, glass-ceramic and/or ceramicmaterial.

In embodiments of the invention, the surfaces of the molded article 38are of optical quality without further processing. In such embodiments,the surfaces of the article 38 assume the topography imparted by theinterior surfaces of the mold 32. As used herein, “optical quality”refers to the suitability of a surface or article for use inapplications in the optics field.

In some embodiments, the first material may not completely decomposeduring the molding process, and the surfaces of the molded article 38may be polished and/or further treated (e.g., with solvent) to removeremaining residue.

Referring to FIG. 4, another embodiment of a moldable article 110 isshown. Article 110 includes first barrier 112 defining an interior spacedivided into a first interior space 114 a and a second interior space114 b. Interior spaces 114 a, 114 b are depicted as substantially equalin their interior capacity or volume, with the two spaces beingseparated by a single partition 113. As previously described for thearticle 10 of FIG. 1, the atmospheres in each of the interior spaces 114a and 114 b may be different than the atmosphere surrounding themoldable article 110, and it will be appreciated that interior spaces114 a, 114 b may have inner atmospheres that are the same as one anotheror they may be different from one another. The atmospheres in interiorspaces 114 a and/or 114 b are substantially free of moisture, and insome embodiments, the interior spaces comprise inert gas. In someembodiments, interior spaces 114 a and/or 114 b have been evacuated toprovide a vacuum or near vacuum state.

A volume of first glass particles 116a comprising a first glass areincluded within the first interior space 114 a. Likewise, apredetermined amount of second glass particles 116 b are included withinthe second interior space 114 b. The amount of first particles 116 a ininterior space 114 a may be the same as or different than the amount ofsecond particles 116 b within interior space 114 b. Second particles 116b comprise a second glass. At least one of the first glass or the secondglass comprise non-traditional glass materials, as previously described.First glass and second glass may be the same glass material or they maybe different.

In some embodiments of the invention, second glass particles 116 b areidentical to first glass particles 116 a in that the first glass is ofthe same composition as the second glass. In other embodiments, thefirst glass is of a different composition than that of the second glass.

In embodiments wherein both first and second glasses are non-traditionalglasses, at least one of the glasses may comprise less than 40 percent(or less than 35%, 30%, 25%, 20%, 15%, 10%, 5% or even 0%) by weightglass collectively SiO₂, B₂O₃, and P₂O₅, based on the total weight ofthe glass. The plurality of second particles are moldable at a secondmolding temperature in that they will begin to soften and coalesce(e.g., during a molding operation) at or above the second moldingtemperature, and the second molding temperature may be the same as ordifferent than the first molding temperature. In the variousembodiments, the first decomposition temperature is less than both thefirst molding temperature and the second molding temperature.

First barrier 112 is made from materials as previously described withreference to the moldable article 10 (FIG. 1). Partition 113 istypically made from the same material as first barrier 112, althoughsome embodiments may include a partition made from material differentthan that used for barrier 112.

Referring to FIG. 5, a schematic illustration of a process is shown forthe manufacture of the moldable article 110 and for its subsequent usein a molding process to provide a molded glass article 138. A measuredquantity of first glass particles 116 a are initially heated within acontainer 120 to remove water, and a measured quantity of second glassparticles 116 b are heated in a second container 121, also to removewater. The containers 120, 121 may be heated at a separate heatingstation (not shown) which can include an oven, a heating mantle or thelike.

Following heating to remove moisture, the containers 120 and 121 may besealed to prevent moisture from returning to the particles as they areallowed to cool. First glass particles 116 a are transferred fromcontainer 120 into the first interior space 114 a of sealable container126. Funnel 128 is shown as an optional means to facilitate the transferof the glass particles 116 a. Second glass particles 116 b aretransferred from container 121 into the second interior space 114 b ofsealable container 126. Funnel 129 is shown as an optional means tofacilitate the transfer of the particles 116 b. Following transfer ofthe glass particles, sealable container 126 is sealed along its openedside 130 to provide moldable article 110.

In some embodiments of the invention, the sealable container 126 ispurged with inert gas prior to sealing. In other embodiments, interiorspaces 114 a and 114 b are sealed following evacuation to provide areduced pressure (e.g., vacuum or near vacuum conditions) within theinterior spaces.

The moldable article 110 is suitable for use in a molding process inwhich the article is placed in an opened mold cavity 134 of mold 132with the respective interior spaces 114 a and 114 b oriented withrespect to one another so that one of the interior spaces and itscontents (e.g., the glass particles 116 a or 116 b) lay on top of theother interior space and its contents. In this orientation, particles116 a and 116 b form two layers of glass material, stacked one on top ofthe other. In the compression molding process of FIG. 5, cavity 134 isinitially opened to receive the article 110 and is configured to beheated to an elevated temperature. With moldable article 110 disposedwithin cavity 134, the mold 132 is closed and is heated to apredetermined temperature. Pressure is applied to the article 110 withplug member 136 to compress the glass particles within the cavity 134.

In the various embodiments of the invention, the first barrier 112 ofthe moldable article 110 will substantially decompose at or above acharacteristic decomposition temperature. In some embodiments,decomposition of the first barrier 112 removes substantially all of thefirst material of the barrier. Thereafter, the temperature of the mold132 is increased to heat the glass particles 116 a and 116 b to amolding temperature at which the particles will soften and coalesce. Themold 132 is cooled and the resulting molded article 138 may be removedfrom the cavity 134. Molded article 138 is a two layered composite witha first layer 138 a resulting from molding of the first particles 116 aand the second layer 138 b resulting from the second particles 116 b. Insome embodiments, the first material of first barrier 112 may notcompletely decompose during the molding process so that the surfaces ofthe molded article 138 may require polishing and/or another treatment(e.g., cleaning with a solvent) to remove any remaining residue. Atleast one of the layers 138 a or 138 b comprise a material derived froma non-traditional glass, as described herein.

In still other embodiments, molded articles similar to molded article138 may be made by stacking individual moldable articles (e.g., similarto article 10, FIG. 1) in a mold cavity and molding the moldablearticles in the same manner as previously described. Multilayeredarticles similar to article 138 may be particularly useful as opticallenses, for example. In such embodiments, molded layers 138 a and 138 bmay each have one or more different properties such as differentrefractive indexes or the like. In various embodiments, molded article138 may comprise glass, ceramic and/or glass-ceramic material resultingfrom the molding of non-traditional glass. In some embodiments, thenon-traditional glass particles are coalesced and are at least partiallycrystallized. In some embodiments, the glass is heat treated in a mannerthat increases the crystallinity of the glass and provides glass-ceramicor ceramic material.

Referring now to FIG. 8, a multilayered molded article 168 is shown. Thearticle 168 may be made according to an embodiment of the invention.Molded layers 168 a, 168 b, and 168 c occupy discrete positions withinthe stacked arrangement. In some embodiments, each of the molded layers168 a, 168 b, and 168 c is made from a different glass composition toprovide a molded layer with a refractive index that is different thanthe refractive index of either of the other two layers. In embodimentsin which the article 168 is a gradient index lens, for example, layers168 a and 168 c may comprise a high refractive index glass while themiddle layer 168 b may be made of a low refractive index glass. At leastone of the layers 168 a, 168 b, and/or 168 c is the molded product of anon-traditional glass, as previously described, and molding of thenon-traditional glass may result in glass, ceramic and/or glass-ceramicmaterials in one or more of the layers 168 a, 168 b or 168 c of moldedarticle 168. The article 168 may be made from a moldable articlecomprising three different interior spaces, for example, each interiorspace containing a separate set of glass particles. Alternatively, thearticle 168 may be made by simultaneously molding three moldablearticles stacked on top of one another within a mold cavity, eachmoldable article containing its own separate set of glass particles.Through the molding process, as previously described, each of themoldable articles would result in the creation of a layer in thefinished article 168.

FIG. 6 depicts a moldable article 210 configured according to stillanother embodiment of the invention. Article 210 is a container having afirst barrier 212 and an interior space divided into a first interiorspace 214 a and a second interior space 214 b. Interior spaces 214 a,214 b each have inner atmospheres as previously described with respectto the embodiments of FIGS. 1 and 4. A predetermined amount of firstglass particles 216 a are included within the first interior space 214a, and a predetermined amount of second glass particles 216 b areincluded within second interior space 214 b. In the depicted embodiment,interior space 214 a is larger than interior space 214 b, and the amountof first particles 216 a in first interior space 214 a is greater thanthe amount of second particles 216 b within second interior space 214 b.As in the previous embodiments, the particles 216 a are of a first glasscomposition which may be different than the second glass composition ofparticles 216 b. In general, first and second glass particles may beselected to provide different properties to the final molded articlesuch as different refractive indexes, for example. At least one of thefirst glass particles 216 a or the second glass particles 216 b comprisenon-traditional glass, as previously described.

Moldable article 210 may be made using a combination of individualcontainers wherein first barrier 212 is made of a flexible material suchas a polymeric material, as already described. In such an embodiment,the single container is a ‘bag’ or a flexible-walled container with asingle opened end leading into its interior space. Second interior space214 b may be created by providing heat sealed edges 215 a, 215 b, 215 cto form three sides of the second interior space 214 b. A fourth heatsealed edge 215 d is formed after the interior space 214 b is filledwith glass particles 216 b. In FIG. 6, second interior space 214 b ispositioned in the center of first interior space 214 b. Alternatively,the second interior space may be positioned elsewhere within the largerfirst interior space 214 b, depending on the configuration desired forthe final molded article. It will also be appreciated that, in someembodiments, more than two interior spaces (e.g., a third interiorspace, a fourth interior space and the like) may be associated with thesame moldable article, each such interior space containing a volume ofglass particles with at least one of the volumes of glass particlescomprising a non-traditional glass, as previously described.

Moldable article 210 may be used in a molding process, as previouslydescribed with respect to the embodiments of FIGS. 1-5. The resultingmolded article will include at least two different molded portions, oneof the molded portions resulting from processing of the first glassparticles 214 a and another molded portion made from processing of thesecond glass particles 214 b.

Molded article 238, shown in FIG. 9, is of the type obtained from amolding process involving moldable article 210 of FIG. 6. Article 238includes a first or outer molded portion 238 a and a second or innermolded portion 238 b nested within and affixed to the outer portion 238a. It will be appreciated that the depicted shapes of molded portions238 a, 238 b are merely illustrative, and that other shapes are withinthe scope of this disclosure and may be readily obtained merely byaltering the design of the mold used to make the molded articles, forexample. At least one of the layers of the molded article 238 resultsfrom the molding of non-traditional glass materials, as previouslydescribed, so that such a layer may comprise glass, ceramic and/orglass-ceramic materials.

Other embodiments are contemplated wherein the moldable article issimilar to the article 210 in FIG. 6, but wherein the second interiorspace (e.g., comparable to space 114 b) is actually comprised of aseparate moldable article placed within the interior space of a largermoldable article (e.g., comparable to interior space 214 a). In otherwords, embodiments of the invention include those wherein separatemoldable articles are included in the interior space of another moldablearticle. Each of the separate interior spaces of each moldable articleinclude a volume of glass particles. At least one of the volumes ofglass particles comprise a non-traditional glass, as previouslydescribed.

In still other embodiments, molded articles may be made according to thepresent invention wherein the articles include both glass and non-glassportions affixed to one another. Article 338 is depicted in FIG. 10 andincludes two components, molded glass portion 338 b placed within acircular, non-glass, first portion 338 a (e.g., a frame). Molded glassportion 338 b comprises a non-traditional glass as previously described.The circular non-glass portion 338 a may be made from any of a varietyof other materials including polymeric materials, metallic materials orthe like. Prior to forming the finished molded article 338, thenon-glass portion 338 a may be pre-formed and placed within a moldcavity. In the molding operation, the non-glass portion 338 a is placedin the mold and a moldable article (as described herein) is positionedin the center of the non-glass portion 338 a within the mold. A moldingprocess may be performed to form article 338 having molded glass portion338 b positioned within the center of portion 338 a. During the moldingoperation, glass particles in the moldable article coalesce while alsobonding to the non-glass portion to form a finished article 338 withportions 338 a and 338 b affixed to one another.

The person of ordinary skill in the art will appreciate that othermulti-component articles may also be made using the moldable articles ofthe present invention. Such multi-component molded articles can includeglass and non-glass portions arranged as needed or desired. Another suchmulti-component molded article 448 is depicted in FIG. 11. The article448 includes three components 448 a, 448 b, and 448 c. At least one ofthe molded components comprises a material derived from anon-traditional glass, as previously described. Article 448 results frommolding at least one moldable article, as described herein.

In still another embodiment, a moldable article 310 is depicted in FIG.7. As in the previously described embodiments, article 310 is acontainer having a first barrier 312. Instead of being flexible,however, first barrier 312 is made of a shaped, more rigid, material. InFIG. 7, the molded article 310 has a hemispherical shape with a concavecenter portion 311 (e.g., it is cup-shaped). A plurality of glassparticles 316 occupy interior space 314 within the article 310, and theinterior space 314 has a substantially moisture-free inner atmosphere,as previously described. First barrier 312 comprises a first materialthat will decompose as the mold is heated and pressurized during amolding operation. Decomposition of the barrier 312 occurs at adecomposition temperature substantially less than the moldingtemperature of the glass particles 316. Moldable article 310 is shapedto nest within the mold cavity 334, with center portion 311 dimensionedto receive the mold's plug member 336 therein. Molding the cup-shapedarticle 310 results in a similarly shaped molded article. While theshape of article 310 has been somewhat exaggerated for the purposes ofdescribing this embodiment, it will be appreciated that shape of themoldable article will facilitate the formation of a similarly shapedmolded article such as a concave optical lens, for example.

Use of a rigid first material for the barrier 312 serves to hold theplurality of glass particles 316 in a predetermined cup-shapedconfiguration. In the compression molding process, cavity 334 is heatedto an elevated temperature and pressure is applied to the article 310with plug member 336 extending from the mold top 335 into concave centerportion 311. As the mold reaches the decomposition temperature of thefirst material, the barrier 312 will decompose and the glass particles316 will soften and coalesce. As the temperature continues to rise tothe first molding temperature, the particles 316 begin to soften and tocoalesce into a molded form. Upon cooling, the glass will solidify andthe molded article can be removed from the mold cavity 334. Theresulting molded article may comprise glass, glass-ceramic and/orceramic material.

It will also be appreciated by the person of ordinary skill thatvariations to the rigid moldable article 310 are obtainable and areentirely within the scope of the invention. For example, the moldedarticle may be provided in a different shape and/or with multiplechambers, each chamber including a separate plurality of glass particlestherein, with at least one of the chambers containing a pluralitymicroparticles comprising non-traditional glass materials as previouslydescribed. All such embodiments are within the scope of the invention.

The use of a moldable article according to an embodiment of theinvention, provides an improved molding process for glass particles, andespecially for glass microspheres. The various embodiments of theinvention provide a means to initially prepare a plurality of glassparticles for a molding process and thereafter preserve the particles ina ready-state for an undetermined period of time. Moisture as well ascarbon and dirt are known contaminants in the molding of small particlessuch as microspheres. Such contaminants may be picked up by handling theparticles, during placement of the particles into a mold cavity, and/orduring pressurization of the mold cavity. Contamination can beproblematic because it can cause structural defects in the final moldedglass article. In the molding of optical lenses, for example, structuraldefects can result in undesirable optical properties in the finishedlens. In addition to contamination caused be dirt or the like, smallparticles (e.g., microparticles) can pick up static charge that furthercomplicates the handling of the particles, especially during placementof the particles into a mold cavity, for example.

The moldable articles of the invention facilitate the molding process byallowing for the easy deposition of glass particles into a mold cavitywithout concern for retained moisture and without the difficulties ofhandling particles that are statically charged. A maker of glassparticles, for example, can utilize the invention to prepare theparticles for a molding operation that may be performed by an outsidevendor, a customer or the like. Vendors and customers using the glassparticles in a molding process are thus assured of the purity andcleanliness of the packaged particles. Moreover, any of a variety ofmolded articles may be provided including, for example, single layeredarticles as well as multilayered articles.

EXAMPLES

The following non-limiting Examples further illustrate the embodimentsof the present invention.

Example 1

Twenty grams of glass microparticles were deposited in a glass jar anddried in an oven for 16 hours at 130° C. The microparticles were made ofa non-traditional glass having a composition represented as La₂O₃ Al₂O₃Zr0 ₂ Gd₂O₃. The jar was sealed and allowed to cool. The microparticleswere poured into a flexible container (e.g., an envelope) made of 2 mil(0.051 mm) polyethylene film and the envelope was heat sealed. Theenvelope was positioned in a mold cavity. The mold was heated to ˜900°C. and pressurized, burning off the polyethylene film and reshaping thespherical microparticles into a consolidated article with the shape ofthe mold cavity. The mold was cooled and the glass article was removedand the surfaces were polished. A clear molded glass article wasproduced.

Example 2

Five hundred grams of La₂O₃ Al₂O₃ Zr0 ₂ Gd₂O₃ spherical glassmicroparticles were dried, placed in a flexible polyethylene envelopeand heat sealed to provide a moldable article made of 4 mil (0.102 mm)thick polyethylene film. Carbon plates were used to construct a moldcavity having the dimensions of 5 in.×5 in.×˜⅜ in. (12.7 cm×12.7 cm×0.95cm). The moldable article was positioned in this mold cavity and thecavity was covered and sealed with additional carbon plates. The moldwas heated to 870° C. and pressurized, compressing the microparticlesinto a solid molded article. The polyethylene film was burned off duringthe heating process.

While various embodiments have been described and exemplified herein,the person of ordinary skill in the art will appreciate that changes andmodifications may be made to the described embodiments without departingfrom the spirit and scope of the invention.

1. A moldable article, comprising: A first container comprising a firstbarrier, the first barrier comprised of a first material, and aninterior space within the first barrier; A plurality of first glassparticles contained within the interior space and comprising a firstglass, the plurality of first glass particles being moldable at a firstmolding temperature, the first glass having a first glass transitiontemperature and a first crystallization onset temperature, thedifference between the first glass transition temperature and the firstcrystallization onset temperature being at least about 5° K., the firstglass having a composition comprising at least two metal oxides, from 0to less than 20% by weight SiO₂, from 0 to less than 20% by weight B₂O₃,and from 0 to less than 40% by weight P₂O₅; and Wherein, the firstmaterial has a first decomposition temperature less than the firstmolding temperature.
 2. The article according to claim 1 wherein thefirst glass particles comprise microparticles.
 3. The article accordingto claim 1 wherein the first material comprises a polymer.
 4. Thearticle according to claim 3 wherein the polymer is selected from thegroup consisting of polyamide, poly methyl methacrylate,polyisobutylene, polycarbonate, polyethylene carbonate, polypropylenecarbonate, polybutylene terephthalate, polyetheretherketone,polyethylene, polypropylene, polyphenylene oxide, polystyrene aromaticpolyesters, and combinations of two or more of the foregoing.
 5. Thearticle according to claim 4 wherein the polyamide is selected from thegroup consisting of nylon 6, nylon 66 and combinations thereof.
 6. Thearticle according to claim 4 wherein the polyethylene is selected fromthe group consisting of low density polyethylene, high densitypolyethylene, medium density polyethylene and combinations of two ormore of the foregoing.
 7. The article according to claim 4 wherein thepolyethylene is low density polyethylene.
 8. The article according toclaim 1 wherein the first material is flexible.
 9. The article accordingto claim 1 wherein the first material is rigid.
 10. The articleaccording to claim 1 wherein the first material is paper.
 11. Thearticle according to claim 1 wherein the interior space is substantiallyfree of water vapor.
 12. The article according to claim 1 wherein theinterior space has an atmosphere comprising an inert gas selected fromthe group consisting of helium, neon, krypton, argon, xenon, nitrogenand combinations of two or more of the foregoing.
 13. The articleaccording to claim 1 wherein the interior space is divided into at leasta first interior space and a second interior space with the plurality offirst glass particles contained within the first interior space and aplurality of second glass particles contained within the second interiorspace, the second glass particles comprising a second glass having acomposition different than the composition of the first glass.
 14. Thearticle according to claim 13 wherein the second glass particlescomprise microparticles, the second glass having a second glasstransition temperature and a second crystallization onset temperature,the difference between the second glass transition temperature and thesecond crystallization onset temperature is at least about 5° K., thesecond glass comprising at least two metal oxides, from 0 to less than20% by weight SiO₂, from 0 to less than 20% by weight B₂O₃, and from 0to less than 40% by weight P₂O₅.
 15. The article according to claim 1further comprising: A second container comprising a second barrier, thesecond barrier comprised of a second material, and a second interiorspace within the second barrier, the second container being whollywithin the interior space of the first container; A plurality of secondglass particles contained within the second interior space so that theplurality of second glass particles and the plurality of first glassparticles are separated from one another, the plurality of second glassparticles comprising a second glass, the plurality of second glassparticles being moldable at a second molding temperature.
 16. Thearticle according to claim 15 wherein the second glass has a secondglass transition temperature and a second crystallization onsettemperature, the difference between the second glass transitiontemperature and the second crystallization onset temperature is at leastabout 5° K, the second glass having a composition different than thecomposition of the first glass and comprising at least two metal oxides,from 0 to less than 20% by weight SiO₂, from 0 to less than 20% byweight B₂O₃, and from 0 to less than 40% by weight P₂O₅.
 17. The articleaccording to claim 15 wherein the second material has a seconddecomposition temperature less than the second molding temperature. 18.The article according to claim 15 wherein the second material is thesame as the first material.
 19. The article according to claim 1 whereinthe first molding temperature is about 300° C. or greater.
 20. A methodof making a moldable article, the method comprising: Placing a pluralityof first glass particles in a first receptacle, the plurality of firstglass particles being moldable at a first molding temperature, the firstglass having a first glass transition temperature and a firstcrystallization onset temperature, the difference between the firstglass transition temperature and the first crystallization onsettemperature being at least about 5° K., the first glass having acomposition comprising at least two metal oxides; Removing entrappedmoisture from the first glass particles; and Sealing the firstreceptacle to form a first container comprising a first barrier, thefirst barrier defining an interior space, the plurality of firstmicroparticles occupying at least a portion of the interior space,wherein the interior space is substantially free of water, and whereinthe first barrier comprises a first material having a firstdecomposition temperature lower than the first molding temperature.21-39. (canceled)